1. Field of Invention
The present invention relates to circuits for reading and writing data to and from devices, and more particularly to reduced pin count integrated circuits and methods of reducing the pin count in a device capable of writing data to and reading data from external devices.
2. Discussion of Related Art
As consumer electronic devices and other devices containing integrated circuits shrink in physical size due to consumer preference, power savings considerations, etc., the integration density of integrated circuits (ICs) within these devices increases. In many instances, designs of certain types of integrated circuits or electronic devices have become pin count limited. The number of input/output (I/O) pins on a final IC package are often desired to be as low as possible, and in some instances a single additional pin may make the difference between a go or no go decision for inclusion of a certain IC in a particular product. Further, in many device types, as the cost of semiconductor die production continues to drop over time, the cost of the device packaging is becoming a larger portion of the cost of the entire packaged IC. Thus, the savings in packaging costs by the reduction in pin count of the final assembled device is having a greater and greater impact on the total device cost.
As the limit on the number of I/O pins allowed on an integrated circuit package decreases, this may limit the potential functionality of the integrated circuit. This makes it desirable to modify the device design to impart more functionality per pin. In some integrated circuits, software may be utilized to instruct a device to switch the functionality of one or more pins in different time intervals to carry input or output signals for more than one external device, or to periodically switch one or more pins from performing an output function to performing an input function. These solutions may in some instances put a significant load on the processing ability of the associated device or devices.